Oil spill monitoring via microwave tomography enhanced GPR surveys

• Microwave Tomography enhanced GPR for oil (LNAPL) spill detection and monitoring.
• Full 3D microwave tomography accounting for the vectorial nature of the scattering phenomenon.
• Performance assessment against experimental data gathered in controlled laboratory conditions.

Oil spill detection and monitoring deserve huge attention in environmental protection as well as for timely planning maintenance actions, with the final aim to mitigate soil pollution. In this frame, the requirement for detailed subsurface diagnostics, while performing non-invasive surveys, motivates the use of ground penetrating radar (GPR) systems and their continuous development in order to improve the achievable performance. Moving in this direction, this paper aims at investigating the reconstruction capabilities of a full 3D microwave tomography approach as a tool for pollution characterization and imaging. The microwave tomography approach exploits a Born Approximation based model of the electromagnetic scattering phenomenon and is capable of accounting for the vectorial nature of the wave–material interaction. The reconstruction capabilities are assessed against experimental data referred to oil spill in dry and water saturated sand soils, gathered in laboratory controlled conditions at the Department of Geophysics of the University of São Paulo, Brazil. The provided results state that the full 3D microwave tomography approach is able to gain accurate images of the surveyed scenarios allowing to acquire information on the oil diffusion process in both the considered soils.